The First Conversion of Primary Alkyl Halides to Nitroalkanes under Aqueous Medium
Roberto Ballini, Luciano Barboni, and Guido Giarlo
J. Org. Chem., 2004, 69 (20), pp 6907–6908
DOI: 10.1021/jo049048b
Abstract
Primary alkyl bromides and iodides can be converted into the corresponding primary nitroalkanes and α,ω-dinitroalkanes in good yields by using silver nitrate in aqueous medium.
Paragraph 1
Nitroalkanes serve as useful synthetic intermediates due to their carbon-carbon bond-forming capabilities and functionalization of the nitro group.
Nitroalkanes can be obtained in a variety of ways: (i) nitration of aliphatic hydrocarbons, (ii) conversion of other functionalities to the nitro group, and (iii) nitration of alkyl halides with metal nitrates (e.g. Victor-Meyer reaction and Kornblum reaction).
While preparation of nitroalkanes from their corresponding alkyl halides is one of the most commonly used methods, some of the major drawbacks include long reaction times, toxic solvents, tedious workup, low yields, and difficulty in purifying products.
Paragraph 2
Organic reactions carried out in water have become increasingly popular due to the fact that it is environmentally friendly and allows for adequate control of the reaction.
The authors claim that they have found the first methodology for the conversion of primary alkyl halides to nitroalkanes under aqueous medium by using four equivalents of silver nitrate and obtaining “satisfactory to good yields.”
Paragraph 3
It was found that alkyl bromides showed higher reactivity than alkyl iodides and other functionalities were preserved under the milder conditions.
The authors allude to the possibility of a one-pot synthesis of α,ω- dinitroalkanes from the corresponding diiodo structures.
Paragraph 4
As confirmed by NMR and GC, the formation of alkyl nitrite byproducts was strongly depressed under these reaction conditions.
A catalytic amount of cetyltrimethylammonium bromide (CTABr) was shown to offer no improvement.
This method failed for secondary halo derivatives due to the prevalent formation of side products.
Paragraph 5
This method offers a considerable number of important advantages over previous standard procedures.
Paragraph 6 (Conclusion)
The first eco-friendly procedure for the conversion of primary alkyl halides to nitroalkanes under aqueous medium offers results of great interest due to the increasing demand for aliphatic nitro compounds.
Experimental Section
The nitration procedure is described in detail along with the aqueous workup and purification technique.
Spectra (e.g. 1H NMR, 13C NMR, GC-MS, and IR) are presented for the various compounds.
Acknowledgements
The authors acknowledge the University of Camerino-Italy and MIUR-Italy for their support.
Roberto Ballini, Luciano Barboni, and Guido Giarlo
J. Org. Chem., 2004, 69 (20), pp 6907–6908
DOI: 10.1021/jo049048b
Abstract
Primary alkyl bromides and iodides can be converted into the corresponding primary nitroalkanes and α,ω-dinitroalkanes in good yields by using silver nitrate in aqueous medium.
Paragraph 1
Nitroalkanes serve as useful synthetic intermediates due to their carbon-carbon bond-forming capabilities and functionalization of the nitro group.
Nitroalkanes can be obtained in a variety of ways: (i) nitration of aliphatic hydrocarbons, (ii) conversion of other functionalities to the nitro group, and (iii) nitration of alkyl halides with metal nitrates (e.g. Victor-Meyer reaction and Kornblum reaction).
While preparation of nitroalkanes from their corresponding alkyl halides is one of the most commonly used methods, some of the major drawbacks include long reaction times, toxic solvents, tedious workup, low yields, and difficulty in purifying products.
Paragraph 2
Organic reactions carried out in water have become increasingly popular due to the fact that it is environmentally friendly and allows for adequate control of the reaction.
The authors claim that they have found the first methodology for the conversion of primary alkyl halides to nitroalkanes under aqueous medium by using four equivalents of silver nitrate and obtaining “satisfactory to good yields.”
Paragraph 3
It was found that alkyl bromides showed higher reactivity than alkyl iodides and other functionalities were preserved under the milder conditions.
The authors allude to the possibility of a one-pot synthesis of α,ω- dinitroalkanes from the corresponding diiodo structures.
Paragraph 4
As confirmed by NMR and GC, the formation of alkyl nitrite byproducts was strongly depressed under these reaction conditions.
A catalytic amount of cetyltrimethylammonium bromide (CTABr) was shown to offer no improvement.
This method failed for secondary halo derivatives due to the prevalent formation of side products.
Paragraph 5
This method offers a considerable number of important advantages over previous standard procedures.
Paragraph 6 (Conclusion)
The first eco-friendly procedure for the conversion of primary alkyl halides to nitroalkanes under aqueous medium offers results of great interest due to the increasing demand for aliphatic nitro compounds.
Experimental Section
The nitration procedure is described in detail along with the aqueous workup and purification technique.
Spectra (e.g. 1H NMR, 13C NMR, GC-MS, and IR) are presented for the various compounds.
Acknowledgements
The authors acknowledge the University of Camerino-Italy and MIUR-Italy for their support.